JPH05245132A - X-ray image pickup device - Google Patents

Abstract

PURPOSE:To easily grasp a relation of density and actual existence in an X-ray image by displaying a calibration scale whose density graduation is varied in accordance with a density center value and density width set by window setting, an image of an object to be photographed, and a relation of a decrease weakness degree corresponding to an image pickup condition and thickness of a calibration material, on a screen of an indicator. CONSTITUTION:A cursor 93 is moved and clicked to an interest point of an X-ray image 90 of an object to be photographed, displayed on a CRT display device. Subsequently, when the cursor 93 is moved and clicked to the part of desired density width of a density width setting display 92, an image of desired density width in which a decrease weakness degree in the interest point is a density center value is obtained. Also, simultaneously, density of a density display area 91a is varied so that a relation of density of a density display area 91a of a calibration scale 91 and a decrease weakness degree displayed on a decrease weakness degree display part 91b coincides with a window setting state. Moreover, as for a display of a calibration material thickness display part 91c, a relation of a display of the decrease weakness degree display part 91c and thickness of the calibration material comes to correspond to an image pickup condition of the X-ray image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray imaging apparatus suitable for use in chest imaging, for example, and more specifically,
CRT based on the spatial distribution of X-ray dose transmitted through the subject
X of the method that displays the digital image of the subject on the screen such as
The present invention relates to a line imaging device.

[0002]

2. Description of the Related Art In an X-ray image pickup apparatus for measuring a spatial distribution of an X-ray dose transmitted through an object and constructing a digital image using the measurement result as pixel density information, a CRT is usually used as an image display. Has been done.

By the way, a CRT generally has a narrow density gradation range, and even if the X-ray spatial distribution is measured over a wide density range, the CRT display screen is out of a predetermined density range based on its gradation reproduction characteristics. Pixels having a density of are displayed as a saturated saturated density value, that is, as white or black at the same level.

Therefore, conventionally, in order to make the image easier to see, processing called window processing or the like is performed to emphasize the contrast of the image of the region of interest.
According to this processing, for example, data relating to the degree of X-ray attenuation of each pixel based on the measurement result of the spatial distribution of the X-ray dose is temporarily stored in the memory, and the degree of attenuation corresponding to the central concentration of the concentration range displayable on the CRT is stored. By setting the data value (density center value) and the data value width (density width) that also corresponds to the entire density range that can be displayed, the data with a value within that width is gradation converted to display memory. , And only the region of interest is displayed in high gradation on the CRT screen.

[0005]

By the way, when the region of interest is selected and the image in which the contrast of the region is emphasized is displayed by the above window processing, the shape of the subject can be easily grasped from the image. , The relationship between the concentration and the actual (organization) on the screen is not clear, and it is difficult to grasp quantitatively. Further, regardless of whether window processing is executed or not, if the imaging condition changes, the degree of X-ray attenuation changes even for the same subject, and it becomes more difficult to grasp the relationship between the density on the image and the reality.

The present invention has been made in view of the above point, and it is possible to easily grasp the relationship between the density and the reality in the X-ray image displayed on the screen, and therefore, the comparison and the quantification in the image reading work. The purpose of the present invention is to provide an X-ray imaging device that can be easily examined.

[0007]

In order to achieve the above object, the X-ray image pickup apparatus of the present invention determines the degree of X-ray attenuation for each pixel based on the measurement result of the spatial distribution of X-rays transmitted through the object. The original image data memory for storing such data, the setting means for setting the data value relating to the attenuation degree to be associated with the density range displayed on the screen, and the respective contents in the original image data memory based on the setting contents by the setting means. Calculation means for converting the data into the density data of each pixel, a display memory for storing the calculation result for each pixel, a subject image based on the stored contents of the display memory, and a scale based on the set contents by the setting means It has a display that displays a calibration scale that changes the upper density gradation, and a calibration memory that stores the relationship between attenuation-related data and calibration material thickness for each of multiple imaging conditions. The kale, characterized by the configuration and data according to the attenuation of the thickness is displayed together calibration member corresponding to the imaging condition (see FIG. 2) as.

[0008]

[Function] On the screen of the display, a calibration scale whose density gradation changes according to the set density center value and density width is displayed together with the subject image. Since the relationship between the attenuation data and the thickness of the calibration material is also shown, the density at any position of the subject image becomes the thickness of the calibration material even if arbitrary contrast enhancement is performed by window processing. You can see at a glance how much it is. Here, since the relationship between the thickness of the calibration material and the reality can be known in advance for each imaging condition as illustrated in FIG. 3, what imaging condition is adopted or what window setting is performed. Also, it is possible to always grasp the relationship between the density on the image and the reality.

[0009]

1 is a block diagram showing the configuration of an embodiment of the present invention, showing an example in which the present invention is applied to a photon counting type X-ray imaging apparatus. In addition, Figure 2 shows the CRT
11 is a front view showing an example of a display screen of the display device 9. FIG.

The X-ray sensor array 1 has a plurality of X-ray sensors 1a ... 1n arranged one-dimensionally or two-dimensionally, and each X-ray sensor 1a ... 1n corresponds to a pixel. Each output is guided to a comparator 3a..3n via a charge-voltage converter 2a..2n, where only signals having a predetermined peak value are discriminated and introduced into each counter 4a..4n.

The count value of each counter 4a ... 4n is X
The data is sampled by the computer 5 via the input / output interface 11 at a predetermined timing synchronized with the scanning of the line sensor array 1. Each count value serves as data representing the dose of X-rays transmitted through the subject on the optical path corresponding to each pixel. In the computer 5, each count value n and the count value N in the absence of the subject are used. ₀
Is used to calculate the attenuation degree A for each pixel by A = −log (n / N ₀ ), and each is stored in the address for each pixel set in the original image data memory 6.

In addition to the original image data memory 6, the computer 5 includes a display memory 7, a calibration scale memory 8 and C.
The RT display device 9 and the mouse 10 are connected,
Similar to the original image data memory 6, the display memory 7 has an address for storing density data for each pixel and an address corresponding to a calibration scale 91 and a density width setting display section 92 described later. The mouse 10 is for moving a cursor on the display screen of the CRT display device 9, and the position of the cursor is incorporated into the computer 5 as an address signal.

The calibration scale memory 8 stores a plurality of sets of relationships between the degree of attenuation and the thickness of the calibration material corresponding to a plurality of imaging conditions selectable by the X-ray imaging apparatus. That is,
As illustrated in FIG. 3, for example, the degree of attenuation of each actual material in the chest tissue has a deep correlation with the degree of attenuation in each thickness when an acrylic plate is used as the calibration material, but when the imaging conditions are changed, The relationship between the thickness and the degree of attenuation is different. The calibration scale memory 8 stores such a relationship between the attenuation degree and the calibration material thickness for each imaging condition.

The CRT display device 9 comprises a CRT and its controller, and has an X-ray image 90 based on the contents of the display memory 7, a calibration scale 91 and a density width setting display section 92.
The image in which the cursor 93 is combined can be displayed in response to the display of. Of these, the density range setting display section 92
This is a display for setting which of the three levels of attenuation levels ± 1, ± 0.3 and ± 0.1 corresponds to the entire density range of the CRT display device 9.

The calibration scale 91 has a density display area 91a having a plurality of areas arranged in a straight line and having sequentially different densities.
And an attenuation degree display section 91b and a calibration material thickness display section 91c displayed on the left and right sides thereof. Of these, a constant numerical value is always displayed at a fixed position on the attenuation degree display portion 91b.

The computer 5 converts the attenuation data of each pixel in the original image data memory 6 into density data and stores it in the display memory 7 by the following processing, and also calibrates the display memory 7. The density data of each area of the density display area 91c of the scale 91 is determined, and further the value and position to be displayed on the calibration material thickness display portion 91c of the calibration scale 91 are determined.

That is, by operating the mouse 10, the attenuation level data at the pixel designated by the cursor 93 on the X-ray image 90 is read from the original image data memory 6 based on the address signal indicating the position of the cursor 93, The data value is used as the density center value of the screen, and the density width designated by the cursor 93 on the density width setting display section 92 is similarly recognized from the address signal by operating the mouse 10, and the width is displayed on the screen. Each attenuation level data in the original image data memory 6 is converted into density data as the entire density range of.

At the same time, each density data to be displayed in each area of the density display area 91a is obtained so that the relationship between the attenuation level and the density matches the display of the attenuation level display section 91b on the calibration scale 91. , To the display memory 7. Then, the computer 5 displays the relationship between the attenuation degree and the calibration material thickness of the corresponding condition from the calibration scale memory 8 based on the imaging condition when X-ray imaging is performed to store the attenuation degree in the original image data memory 6. Then, the display of the calibration material thickness display portion 91c is changed so that the display of the attenuation degree display portion 91b and the display of the calibration material thickness display portion 91c match the read relationship. That is, taking the relationship of FIG. 3 as an example, the display of the calibration material scale 91 is in the state of FIG. 2 when imaged under the condition indicated by A in the figure, and is also imaged under the condition indicated by B. If so, the state becomes as illustrated in FIG.

According to the embodiment of the present invention as described above, the CR
By moving the cursor 93 to the point of interest on the X-ray image 90 of the subject displayed on the T display device 9 and clicking, and moving the cursor 93 to the desired density range of the density range setting display 92 and clicking, An image of a desired density range with the attenuation level at the point of interest as the density center value is obtained on the CRT display device 9. At the same time, the density of the density display area 91a changes so that the relationship between the density of the density display area 91a of the calibration scale 91 and the attenuation level displayed on the attenuation level display section 91b matches the above window setting state. The display of the calibration material thickness display unit 91c is such that the relationship between the display of the attenuation degree display unit 91b and the calibration material thickness corresponds to the imaging condition of the X-ray image.

As described above, under the same imaging condition, the attenuation degree of the actual material has a deep correlation with the attenuation degree at each thickness when an appropriate calibration material is used. By finding the point in the density display area 91a of the calibration scale 91 that matches the density of the point of interest in the X-ray image 90 and reading the corresponding thickness of the calibration material from the calibration material thickness display portion 91c on the right, the imaging conditions and Regardless of the window setting situation, the actual material of the interest point can always be easily estimated.

The method of setting the window is not limited to the above-mentioned embodiment, and may be performed by, for example, an operation button or the upper and lower limits of the density display range may be set by the cursor 93. Good.

As the data stored in the original image data memory 6, in addition to the attenuation degree itself, any data can be adopted as long as it is data related to the attenuation degree. Any data relating to the spatial distribution of the line may be used, but by adopting the degree of attenuation represented by the above formula, the relationship with the thickness of the calibration material becomes linear, which is preferable.

The X-ray detection method is not limited to the photon counting method, and it goes without saying that any method can be adopted as long as the X-ray dose can be obtained for each pixel.

[0024]

As described above, according to the present invention,
On the screen of the display that displays the X-ray image of the subject, a calibration scale in which the density gradation changes according to the density center value and the density width set by the window setting is displayed. , The relationship between the degree of attenuation according to the imaging condition and the thickness of the calibration material is displayed together, whichever imaging condition is used or whatever contrast enhancement is performed by the window processing, It is possible to grasp at a glance how thick the density of the calibration image is at a given position of the subject image, and it is possible to easily estimate the actual material at that position.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a front view showing an example of a display screen of the CRT display device 9.

FIG. 3 is a graph showing the relationship between the difference in attenuation depending on the thickness of the acrylic plate and the attenuation of each tissue during chest imaging.

FIG. 4 is an explanatory diagram of a display example of the calibration scale 91 when the imaging condition is changed in the embodiment of the present invention.

[Explanation of symbols]

 1a..1n X-ray sensor 2a..2n Charge-voltage converter 3a..3n Comparator 4a..4n Counter 5 Computer 6 Original image data memory 7 Display memory 8 Calibration scale memory 9 CRT display device 90 X-ray image 91 Calibration Scale 91a Concentration display area 91b Attenuation degree display section 91c Calibration material thickness display section 92 Concentration width setting display section 93 Cursor 10 Mouse

Claims (1)

[Claims] 1. An apparatus for measuring a spatial distribution of an X-ray dose from an X-ray source through an object, obtaining pixel density data from the measurement result, and displaying an X-ray image on the screen. Original image data memory for storing the data relating to the degree of X-ray attenuation for each pixel based on the above, setting means for setting the data value relating to the degree of attenuation that should correspond to the density range displayed on the screen, and its setting means Based on the setting contents by the above, the calculation means for converting each data in the original image data memory into the density data of each pixel, the display memory for storing the calculation result for each pixel, and the storage contents of the display memory A display for displaying a subject image, a calibration scale in which the density gradation on the scale changes based on the settings made by the setting means, data relating to the above-mentioned attenuation degree for each of a plurality of imaging conditions, and a calibration scale. The calibration scale has a calibration memory for storing the relationship with the thickness of the normal material, and the calibration scale is configured to display the attenuation data and the thickness of the calibration material according to the imaging conditions together. An X-ray imaging device characterized by the above.